CN113739696B - Coordinate measuring machine with vision probe for performing point self-focusing type measuring operation - Google Patents

Abstract

A Coordinate Measuring Machine (CMM) system is provided that includes utilizing a vision probe (e.g., for performing operations for determining and/or measuring a surface profile of a workpiece, etc.). The angular orientation of the vision probe may be adjusted using a rotation mechanism such that the optical axis of the vision probe is directed toward the angled surface of the workpiece (e.g., the optical axis may be approximately perpendicular to the angled workpiece surface in some embodiments). The x-axis, y-axis, and z-axis sliding mechanisms (e.g., moving in mutually orthogonal directions) may together move the vision probe along an image stack acquisition axis (which may be substantially coincident with the optical axis) to an acquisition position to acquire an image stack of the angled workpiece surface. The focus curve data may be determined from an analysis of the image stack indicating a 3-dimensional position of a surface point on the angled surface of the workpiece.

Description

Coordinate measuring machine with vision probe for performing point self-focusing type measurement operations

Technical field

The present disclosure relates to precision metrology, and more particularly to coordinate measuring machines having a movement mechanism capable of moving a measurement probe along multiple axes and at desired angles/directions relative to a workpiece surface.

Background technique

A typically known coordinate measuring machine (CMM) includes a probe, a moving mechanism and a controller. The probe may be a tactile measurement probe having a probe tip that physically contacts the workpiece (ie, object) to be measured. Some examples of tactile probes include contact probes or scanning probes (eg, a probe tip positioned to contact and slide along the surface of a workpiece in order to "scan" it). In operation, the CMM's moving mechanism holds and moves the probe, and the controller controls the moving mechanism. The movement mechanism typically enables the probe to move in mutually orthogonal X, Y, and Z directions.

U.S. Patent 7,660,688, which is incorporated herein by reference in its entirety, discloses an exemplary CMM. As mentioned above, a CMM with a moving mechanism moves the contact point of the tactile scanning probe along the surface of the workpiece. During the movement, the probe is pressed against the workpiece to obtain the displacement of the moving mechanism and probe, and then the CMM synthesizes the displacement to detect the position of the contact point (measurement value), thereby measuring/determining the surface profile of the workpiece based on the detected surface points .

While the use of such CMMs with such tactile probes enables measurement of the surface profile of a workpiece, there are certain limitations associated with such a process (e.g., related to the amount of time required for the process to be performed, the relationship between the probe tip and the workpiece required physical contact, etc.). Techniques that could improve or otherwise enhance the use of CMM measurements or other means to determine the surface profile of a workpiece would be desirable.

Contents of the invention

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

According to one aspect, a coordinate measuring machine system is provided that includes a vision probe, a sliding mechanism arrangement, a rotation mechanism, one or more processors, and a memory coupled to the one or more processors. The vision probe includes a light source and an objective lens. The objective lens inputs image light generated by the workpiece surface illuminated by the light source and transmits the image light along the imaging light path. The objective lens defines the optical axis of the vision probe. The light An axis extends at least between the objective lens and the workpiece surface. The vision probe also includes a camera that receives imaging light transmitted along the imaging optical path and provides an image of the workpiece surface. The sliding mechanism configuration includes an x-axis sliding mechanism, a y-axis sliding mechanism, and a z-axis sliding mechanism, each of which is configured to move the vision probe in mutually orthogonal x-axis, y-axis, and z-axis directions, respectively, within the machine coordinate system. The rotation mechanism is coupled between the z-axis sliding mechanism and the vision probe, and is configured to rotate the vision probe to different angular directions relative to the z-axis of the machine coordinate system. The memory stores program instructions that, when executed by one or more processors, cause the one or more processors to:

Use a rotation mechanism to adjust the direction of the vision probe so that the optical axis of the vision probe points to the surface of the workpiece, where the optical axis of the vision probe is not parallel to the z-axis of the machine coordinate system and corresponds to the image stack acquisition axis;

Acquisition includes an image stack of a plurality of images, each image corresponding to a focused position of the vision probe along an acquisition axis of the image stack; and

Focus curve data is determined based at least in part on analysis of images of the image stack, wherein the focus curve data indicates the 3-dimensional location of a plurality of surface points on the workpiece surface.

Further, the above-mentioned collection image stack includes:

Adjusting a plurality of sliding mechanisms to move the vision probe from a first image acquisition position to a second image acquisition position respectively along the image stack acquisition axis, wherein the vision probe is respectively in the first image acquisition position and the second image acquisition position acquiring a first image and a second image of a plurality of images; and

The plurality of sliding mechanisms are adjusted to move the vision probe from a second image acquisition position also along the image stack acquisition axis to a third image acquisition position, wherein the vision probe acquires a third of the plurality of images at the third image acquisition position image.

According to another aspect, a method of measuring a workpiece surface is provided. The method usually consists of four steps:

Operating a coordinate measuring machine system including: (i) a vision probe configured to image a surface of a workpiece based on image light transmitted along an optical axis of the vision probe; (ii) a sliding mechanism configuration including an x-axis sliding mechanism, a y-axis sliding mechanism, and a z-axis sliding mechanism, each configured to move the vision probe in mutually orthogonal x-axis, y-axis, and z-axis directions, respectively, within the machine coordinate system; and (iii) ) A rotation mechanism coupled between the z-axis sliding mechanism and the vision probe, and configured to rotate the vision probe to different angular directions relative to the z-axis of the machine coordinate system;

Use a rotation mechanism to adjust the direction of the vision probe so that the optical axis of the vision probe points to the surface of the workpiece, where the optical axis of the vision probe is not parallel to the z-axis of the machine coordinate system and corresponds to the image stack acquisition axis;

Acquiring an image stack that includes a plurality of images, each image corresponding to a focused position of the vision probe along an image stack acquisition axis, wherein acquiring the image stack includes: (i) adjusting a plurality of sliding mechanisms to move the vision probe from its respective axis moving the first image acquisition position along the image stack acquisition axis to a second image acquisition position, wherein the vision probe acquires a first image and a second image of the plurality of images at the first image acquisition position and the second image acquisition position, respectively; and (ii) Adjust the plurality of sliding mechanisms to move the vision probe from a second image acquisition position also along the image stack acquisition axis to a third image acquisition position, wherein the vision probe acquires multiple images at the third image acquisition position a third image; and

Focus curve data is determined based at least in part on analysis of images of the image stack, wherein the focus curve data indicates the 3-dimensional location of a plurality of surface points on the workpiece surface.

Description of drawings

1A is a diagram illustrating various components of a coordinate measuring machine (CMM) according to an embodiment;

1B is a diagram schematically illustrating a vision probe coupled to a probe head such as the CMM shown in FIG. 1A;

Figure 2 is a block diagram illustrating various control elements of the CMM such as Figure 1A;

3A is a schematic diagram of a vision probe whose optical axis (OA) is approximately vertical relative to the surface on which the workpiece WP is placed (i.e., OA is parallel to the z-axis of the machine coordinate system);

Figure 3B is a schematic diagram of the vision probe of Figure 3A with its optical axis (OA) oriented at an angle (i.e., not parallel to the z-axis of the machine coordinate system);

Figure 4 is a 2-dimensional perspective view showing that the vision probe moves along the x-axis direction and z-axis direction of the machine coordinate system to acquire an image at the image acquisition position (I);

Figure 5 is a 3-dimensional perspective view showing that the vision probe moves along the x-axis direction, y-axis direction and z-axis direction of the machine coordinate system to acquire an image at the image acquisition position (I);

6A and 6B illustrate an exemplary method of how to determine the relative position/coordinates of points on the workpiece surface along the z-axis direction of the probe coordinate system using a stack of images obtained by a vision probe;

Figure 7A shows a sample workpiece including multiple workpiece surfaces and workpiece features;

Figure 7B is a schematic diagram of a vision probe with its optical axis (OA) and image stack acquisition axis (ISAA) oriented generally vertically (i.e., OA/ISAA parallel to the z-axis of the machine coordinate system);

Figure 7C is a schematic illustration of a vision probe with its optical axis (OA) and image stack acquisition axis (ISAA) oriented at an angle so as to be generally perpendicular to the angled surface of the workpiece of Figure 7A; and

Figure 8 is a flow diagram of a method for measuring a workpiece surface by moving a vision probe at a desired angle/direction relative to the workpiece surface using a CMM system including a movement mechanism configuration such as that described in Figures 1-7C. Acquire image stacks.

Detailed ways

FIG. 1A is a diagram illustrating various components of a coordinate measuring machine (CMM) 100 . As shown in FIG. 1A , the coordinate measuring machine 100 includes a machine body 200 that moves a probe 300 , an operating unit 105 having a manual joystick 106 , and a processing equipment configuration 110 . The machine body 200 includes a panel 210, a moving mechanism arrangement 220 (see also FIG. 2), and a vision probe 300. The moving mechanism configuration 220 includes an X-axis sliding mechanism 225, a Y-axis sliding mechanism 226, and a Z-axis sliding mechanism 227 (Fig. 2), which are disposed on the panel 210 to hold and three-dimensionally move the vision probe relative to the workpiece WP to be measured. Needle 300, as shown in Figure 1A. The movement mechanism arrangement 220 also includes a rotation mechanism 214 .

Specifically, the moving mechanism configuration 220 includes a beam bracket 221 capable of moving in the Ym direction in the machine coordinate system (MCS), a beam 222 bridging between the beam brackets 221, and a beam 222 capable of moving in the Xm direction in the machine coordinate system. The moving column 223 and the Z-axis moving member 224 capable of moving in the Zm direction within the column 223 in the machine coordinate system are as shown in Figure 1 . The X-axis sliding mechanism 225, Y-axis sliding mechanism 226 and Z-axis sliding mechanism 227 shown in Figure 2 are respectively provided between the beam 222 and the column 223, between the panel 210 and the beam bracket 221, and between the column 223 and the Z-axis moving member 224. between. The vision probe 300 is attached to a probe head 213 that includes a rotation mechanism 214 and is attached to and supported by an end of a Z-axis moving member 224 . The rotation mechanism 214 enables the vision probe 300 to rotate relative to the Z-axis moving member 224, which will be described in greater detail below. The X-axis sliding mechanism 225, the Y-axis sliding mechanism 226, and the Z-axis sliding mechanism 227 are each configured to move the probe 300 in the mutually orthogonal X, Y, and Z axis directions within the MCS.

As shown in FIG. 2 , the X-axis sliding mechanism 225 , the Y-axis sliding mechanism 226 and the Z-axis sliding mechanism 227 are respectively provided with an X-axis scale sensor 228 , a Y-axis scale sensor 229 and a Z-axis scale sensor 230 . Therefore, the movement amounts of the vision probe 300 in the X-axis, Y-axis, and Z-axis directions in the machine coordinate system (MCS) can be obtained from the outputs of the X-axis scale sensor 228, the Y-axis scale sensor 229, and the Z-axis scale sensor 230. . In the illustrated embodiment, the moving directions of the X-axis sliding mechanism 225, the Y-axis sliding mechanism 226, and the Z-axis sliding mechanism 227 are respectively consistent with the Xm direction, the Ym direction, and the Zm direction in the machine coordinate system (MCS). In various embodiments, these relatively straightforward correlations and associated components can help ensure a high level of motion and position control/sensing accuracy in the Xm, Ym, and Zm directions as well as relatively simplified processing. Probe head 213 with rotation mechanism 214 includes one or more rotation sensors 215 (see Figure 2) for sensing the angular rotation/position/orientation of vision probe 300, which will be described in more detail below.

In various embodiments, the vision probe 300 may be used to perform operations for determining and/or measuring the surface profile of the workpiece WP. As will be described in greater detail below, the rotation mechanism 214 may be used to adjust the angular orientation of the vision probe 300 such that the optical axis OA of the vision probe is directed toward the angled surface of the workpiece WP (e.g., in some embodiments, the Make the optical axis OA approximately perpendicular to the angled workpiece surface). The x-, y-, and z-axis sliding mechanisms 225, 226, and 227 (e.g., moving in mutually orthogonal directions) may combine to move the vision probe 300 along the image stack acquisition axis (which may generally coincide with the optical axis OA ) moves to the image acquisition position to acquire an image stack of the angled workpiece surface. Focus curve data may be determined from analysis of the image stack (eg, as part of a points-from-focus (PFF) type measurement operation) indicating surface points on the angled surface of the workpiece WP 3D position.

As shown in FIG. 2 , the operating unit 105 is connected to the command portion 402 of the processing device configuration 110 . Various commands can be input to the machine body 200 and the processing device configuration 110 via the operating unit 105 . As shown in FIG. 1A , processing device configuration 110 includes motion controller 140 and host computer system 115 . In various embodiments, the processing device configuration 110 may calculate the required amount based at least in part on the amount of movement of the vision probe 300 moved by the movement mechanism configuration 220 and/or analysis of data obtained by the vision probe 300 (eg, including image stacks). The measured shape coordinates of the workpiece WP, as will be described in more detail below. In various embodiments, the shape coordinates may correspond to the depth map and/or surface topography of the workpiece and/or the workpiece surface, and may be based on the relative positions of surface points on the workpiece (eg, as indicated by the coordinates).

The motion controller 140 of FIG. 1A mainly controls the movement of the vision probe 300. The host computer system 115 processes the movements and positions performed and obtained in the machine body 200 . In this embodiment, a processing device arrangement 110 with the combined functionality of a motion controller 140 and a host computer system 115 is shown in the block diagram of Figure 2 and will be described below. Host computer system 115 includes a computer 120, an input unit 125 such as a keyboard, and an output unit 130 such as a display and a printer.

Those skilled in the art will understand that the host computer system 115 and/or described or usable with the elements and methods described herein may generally be implemented using any suitable computing system or device, including distributed or networked computing environments, etc. Other computing systems and/or control systems. Such computing systems or devices may include one or more general-purpose or special-purpose processors (eg, non-custom or custom devices) that execute software to perform the functions described herein. Software may be stored in memory such as random access memory (RAM), read only memory (ROM), flash memory, etc., or a combination of these components. Software may also be stored on one or more storage devices, such as optical disk-based disks, flash memory devices, or any other type of non-volatile storage medium used to store data. Software may include one or more program modules, which include procedures, routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In a distributed computing environment, the functionality of program modules may be combined or distributed across multiple computing systems or devices and accessed through service calls in wired or wireless configurations.

As shown in FIG. 2 , the processing device configuration 110 includes a command section 402 , a sliding mechanism controller 404 , a position determination section 406 , a vision probe controller 408 , a vision probe data section 410 , an analyzer section 412 and a storage section 414 .

The command section 402 shown in FIG. 2 provides a predetermined command to the sliding mechanism controller 404 (for example, based on the command input by the operation unit 105 or the input unit 125). The command part 402 takes into account, for example, the moving direction, the moving distance, the moving speed, etc., and generates coordinate values in the machine coordinate system as a position command to the moving mechanism configuration 220 for each control cycle to move the vision probe 300 to multiple locations. Location (e.g. image acquisition location, etc.).

The sliding mechanism controller 404 shown in FIG. 2 performs driving control by outputting a driving control signal D in response to a command from the command section 402 to cause current to flow through the x-axis, y-axis, and z-axis sliding in the moving mechanism configuration 220 Electric motors for mechanisms 225, 226 and 227.

In one embodiment position latch 216 communicates with various sensors and/or drive mechanisms to ensure that the coordinates of CMM 100 and vision probe 300 are properly synchronized when images are acquired. More specifically, in various implementations, position latch 216 may be used to help ensure the accuracy of measurements derived from images in the image stack. In various embodiments, operation of position latch 216 enables CMM machine coordinates, which reflect the position of attachment points or other reference points of vision probe 300 during a particular measurement, to be compared with position data determined from vision probe images. (e.g., relative to the position and orientation of the vision probe 300) are appropriately combined. In certain embodiments, position latch 216 may be used to trigger measurements from CMM position sensors (e.g., sensors 215 and 228-230, etc.), which may include scales, encoders, or vision probes tracking in the machine coordinate system. Other sensing elements of the overall position and orientation of needle 300 (eg, including its base position). In some embodiments, position latch 216 may also trigger image acquisition from vision probe 300 (e.g., a trigger signal may be provided for each image in the image stack as part of an image stack, where vision probe 300 Corresponding positions are also synchronized and tracked accordingly for each image acquisition).

Figure IB is a diagram schematically illustrating certain components of the machine body 200 of the CMM 100 and the vision probe 300', which may be similar to the vision probe 300 of Figure IA. As shown in FIG. 1B , the machine body 200 includes a probe head 213 . Probe head 213 receives and transmits probe signals via probe head cable 211 . The probe head 213 is fixed to a coordinate measuring machine quill 217 attached to a Z-axis moving member 224 (or a sliding element such as a spindle) that moves in the Z-axis direction of the machine coordinate system (MCS). end. The probe head 213 is connected to the vision probe 300' at the probe auto-splice connection 231. One implementation of an automatic probe connector is described in greater detail in U.S. Patent No. 9,115,982, the entire contents of which is incorporated herein by reference.

The probe head 213 includes a rotation mechanism 214 (Fig. 2) that in some embodiments rotates 360 degrees in the horizontal plane (eg, the first rotation sensor 215 can sense its angular movement/position/orientation), and may include A U-shaped joint (for example, which enables the connected probe to rotate about a corresponding axis located in the horizontal plane, the second rotation sensor 215 can sense its angular movement/position/orientation, as will be discussed in more detail below with respect to Figure 3B description). Thus, in the particular example of FIG. 1B , the rotation mechanism 214 of the probe head 213 supports rotation of the vision probe 300 ′ about two different axes: first, rotating (rotating) the vision probe 300 ′ about the Z-axis in its current orientation, Next, the vision probe 300' is rotated about the horizontal axis (ie, the axis in the XY plane of the machine coordinate system). The rotation mechanism 214 embodied in the probe head 213 in FIGS. 3A and 3B described below is illustrated as substantially circular, although in various embodiments it may be illustrated as spherical in a three-dimensional representation. A rotation mechanism 214 that includes a spherical (or ball) joint allows the vision probe 300' to move the member 224 relative to the Z-axis within the column 223 and/or rotate about any horizontal axis to a desired angle/orientation relative to the workpiece surface Position the optical axis of vision probe 300' (eg, the workpiece surface may be at an angle relative to the horizontal). Generally, the rotation mechanism 214 is a mechanism for changing the direction of the vision probe 300 (ie, the posture of the vision probe 300), as shown in FIGS. 3A and 3B.

The probe auto-splice connection 231 is an electromechanical connection that rigidly and mechanically secures the probe head 213 in a manner that allows it to be disconnected from one probe and attached to another probe. 300' to Vision Probe. In one embodiment, the probe auto-swap connector 231 may include a first mating auto-swap tip element 234 and a second mating auto-swap tip element 236, wherein the first auto-swap tip element 234 is mounted to the probe head 213, and A second mating auto-exchange connector element 236 is mounted to the vision probe 300'. In one embodiment, the probe auto-tap connector 231 has mating electrical contacts or connectors 235 such that when the probe is attached, the contacts automatically engage and form an electrical connection.

The vision probe 300' may receive at least some of its power and control signals through the autosplice connection 231, with the power and control signals passing through the probe head cable 211, respectively. Signals passed from header connection 231 to video probe 300' are passed through connection 235. As shown in FIG. 1B , video probe 300' includes an auto-swap splice element 236 and a probe assembly 237 mounted to the auto-swap splice element 236 for automatic connection to the CMM 100 via a probe auto-swap connector 231.

In various embodiments, vision probe 300' may also or alternatively have at least some of its power and control signals communicated through cable 211'. In some embodiments, cable 211' may be used as there are a limited number of standard autosplice connections 231 available for wired connections, and more connections may be desired/utilized for vision probe 300' (e.g., as via Select cable 211′ provided). In various embodiments, in addition to certain standard power and/or communication signals, the vision probe 300' may have the ability to provide and/or benefit from optional cables 211' and/or through other transmission mechanisms. additional power and/or additional features/capabilities for communication signals. In various embodiments, power and/or communication signals for vision probe 300' (e.g., as conveyed through cable 211 and/or cable 211') may go to and from vision probe controller 408 and vision probe 300'. Probe data portion 410, as will be described in greater detail below with respect to FIG. 2 .

As shown in FIG. 2 , in some embodiments the machine body 200 of the CMM 100 may include an optional tactile measurement probe 390 including an XYZ sensor 392 in addition to the vision probe 300 ( 300 ′). The tactile measurement probe 390 may be a contact probe, a scanning probe, or the like, which typically has a probe tip that physically contacts the workpiece being measured. In some embodiments, such a tactile measurement probe 390 may be used in addition to/in combination with the vision probe 300 . For example, after the vision probe 300 is used to obtain an image stack and determine the 3-dimensional profile of the workpiece surface, the vision probe 300 may be detached/removed from the CMM 100 (eg, from probe head 213 in Figure IB). Tactile measurement probe 390 may then be subsequently attached to CMM 100 (eg, to probe head 213). To this end, in some examples, the CMM 100 may store different probes (e.g., 300, 390, etc.) on the probe rack and move the probe heads 213 into the appropriate locations for attaching and detaching the different probes. probe. The tactile measurement probe 390 can then be used to physically contact and verify certain measurements or surface points (eg, for surface points that may be difficult to view/determine using the vision probe 300). In various embodiments, the tactile measurement probe 390 may be used for physical applications if there are surface points on the workpiece surface that may be difficult to image/capture and/or partially hidden from view by other parts of the workpiece from the vision probe 300 Touch these surface points to take measurements.

Still referring to FIG. 2 , vision probe 300 may include an illumination arrangement 302 , an objective 304 , and a camera 306 . In the illustrated embodiment, objective 304 and camera 306 are internal to vision probe 300 and are illustrated as dashed boxes in some figures (eg, Figures 3A and 3B). In various embodiments, objective 304 may be a multi-lens optical element and may be selected in a range of magnifications. For example, different objectives with different magnifications are available, and the objective to be used in a vision probe can be selected based on the desired magnification for certain applications (e.g., a relatively high magnification objective can be selected, but there are trade-offs smaller range PFF images, etc.).

In the embodiment of FIGS. 3A and 3B , the lighting configuration 302 may be a ring light (eg, formed from an arrangement of LEDs) disposed at the distal end of the vision probe 300 , although the arrangement of the lighting configuration 302 is not limited to the illustrated implementation. example. For example, lighting arrangement 302 may alternatively be provided as a coaxial lamp. In some embodiments, providing coaxial light may require a different configuration, where there is a beam splitter in the optical axis path within the vision probe 300 to direct the light downward through the objective 304, and where the light source is deflected to the side or Otherwise located within vision probe 300 for directing light to a beam splitter, etc. In certain embodiments, a lighting configuration 302 formed by a ring light (eg, an arrangement of LEDs) may have more efficient lighting configurations 302 than a lighting configuration 302 formed by a coaxial light (which may require a beam splitter and a side-biased light source). Light weight and smaller size and size.

As described above with reference to FIG. 1B , optional probe head cable 211 ′ may be used to carry other signals (e.g., for control of lighting configuration 302 , camera 306 , etc., and/or to provide power to vision probe 300 ), or may be Optionally, cable 211' need not be included, in which case all required wires/signals can pass through probe head 213 (eg, and thus through cable 211).

When used with vision probe 300 only, CMM movement mechanism configuration 220, particularly its sensors (215 and 228-230), can provide measurement output M to position determination portion 406, which determines the machine coordinates of the CMM The position of the probe head 213 (or other connection point or reference position) of the vision probe 300 within the system (MCS). For example, position determination portion 406 may provide X, Y, and Z coordinates for probe head 213 or other attachment points or reference points of vision probe 300 within the machine coordinate system. When the tactile measurement probe 390 is attached, the tactile measurement probe 390 may include a mechanism that allows the probe tip to move (a small amount) relative to the remainder of the tactile measurement probe 390 and a corresponding sensor (eg, XYZ sensor 392 ) that The sensor provides sensor data indicating the position of the probe tip (ie, the probe stylus tip) that actually contacts the workpiece surface in the local coordinate system of the tactile measurement probe 390 . a measurement synchronization trigger signal (eg, provided relative to operation of position latch 216 , etc.) triggers measurements that track the overall position and orientation of tactile measurement probe 390 (eg, of probe head 213 ) in the machine coordinate system, and Local surface measurements are triggered using the tactile measurement probe 390 in the local coordinate system. The position determination portion 406 may use and combine the coordinates measured in the local coordinate system and the position of the tactile measurement probe 390 measured in the machine coordinate system to determine the overall position of the probe tip and thereby the measured/detected surface on the workpiece. point.

In contrast to this determination using the tactile measurement probe 390 , when using the vision probe 300 as described herein for various exemplary embodiments, the position determining portion 406 may only determine the position at the top of the vision probe 300 The position of probe tip 213 (or other reference or connection location). To determine the coordinates of surface points on the workpiece, information from the analysis of the image stack can be used. For example, an image stack (of images at different focus positions) may be acquired by the vision probe 300 , where the relative positions/focus positions of the images in the image stack are with respect to the probe coordinate system (PCS), which in some implementations The mode may be related to the reference position of the probe within the MCS. To determine the overall position of a surface point within a machine coordinate system (MCS), in some embodiments, the PCS position data for the surface point may be converted and/or otherwise combined with the MCS position data to determine the overall ensemble of the surface point Location.

When the vision probe 300 is oriented at an angle (eg, as shown in FIG. 3B ) and therefore the Z-axis of the probe coordinate system (PCS) is oriented at an angle (i.e., corresponding to the optical axis of the vision probe 300 ), the acquired The image stack indicates the relative distance of the workpiece's surface points along the direction of the probe's Z-axis oriented at the angle. In some embodiments, those probe coordinate system (PCS) coordinates may be referred to as the local coordinate system, which may then be combined (e.g., transformed and added) with the MCS coordinates determined for probe head 213 (or other reference location) to it) to determine the overall position of the upper surface point of the workpiece in the MCS. For example, if you want to determine the coordinates of a surface point according to the MCS, the measurement points determined in the probe coordinate system PCS can be converted into MCS coordinates and added to other MCS coordinates of the probe head 213 of the vision probe 300 (or other reference position). Alternatively, if the workpiece itself is assigned its own local coordinate system (LCS), the MCS coordinates determined for the probe head 213 (or other reference position) of the vision probe 300 can be converted or compared with the LCS of the workpiece combination. As yet another example, in some cases, other local coordinate systems may also or alternatively be established (eg, images for image stacking, etc.). Typically, an MCS covers the coordinates of the overall large volume of the CMM 100, while an LCS (eg, such as a PCS) typically covers a smaller volume, and in some cases may often be included within the MCS. In various embodiments, in addition to the Coordinates may also or alternatively be utilized.

In some embodiments, position data with respect to the PCS from the image stack can be utilized relatively independently (eg, with limited or no transformation or combined with coordinates from the MCS or other coordinate system). For example, positional data determined from analysis of the image stack may provide 3D coordinates indicating the 3D position of a surface point on a workpiece surface in terms of PCS or other LCS, which therefore represent/correspond to the 3D profile/surface topography of the workpiece surface. As discussed above, in some embodiments, such data may be combined with other position data represented in the MCS to indicate the overall position of the workpiece surface and surface points within the MCS. However, for certain implementations/analyses/representations etc. it may be desirable to utilize primarily or only positional data determined from the image stack. For example, if the analysis or inspection is primarily to determine the relative positions and/or characteristics of workpiece features on the workpiece surface (e.g., with respect to the distances between such workpiece features on the workpiece surface and/or the 3D dimensions of workpiece features on the surface, etc. etc.), then in some embodiments such data may be determined primarily from analysis of image stacks. More specifically, if the desired analysis/inspection does not require the overall location within the MCS of the workpiece surface and/or workpiece features, the data determined from the image stack may be utilized with limited or no combination with other MCS or other coordinate system coordinates. In addition to analyzing such data, it will be understood that a 3D representation of the workpiece surface (eg, on a display, etc.) can similarly be provided based on analyzed data from the image stack.

As shown in Figure 2, vision probe controller 408 controls vision probe 300 (eg, controls lighting configuration 302 and camera 306, etc., to obtain images of image stacks, etc.). In various implementations, vision probe controller 408 does not necessarily control the movement or focus of vision probe 300 . Rather, these aspects may be controlled by a CMM movement mechanism configuration 220 that moves the vision probe 300 closer to and/or farther from the workpiece to obtain the image stack (i.e., moves the vision probe 300 to each image acquisition position , as illustrated/described below with respect to Figures 4 and 5), where the rotation mechanism 214 can be used to rotate the vision probe 300 to a desired angle/orientation. In various embodiments, the focal distance of vision probe 300 may be determined primarily by objective lens 304 (e.g., the focal distance in front of vision probe 300 may be constant during a measurement operation, as is selected in vision probe 300 /The used objective lens 304 corresponds). Vision probe data section 410 receives the output of vision probe 300 (ie, the image data for the image of the image stack). Analyzer portion 412 may be used to perform correlation analysis, such as point autofocus (PFF) analysis or other analysis of image stacking, to determine the relative position of each surface point on the workpiece surface along the probe Z-axis direction to determine the workpiece surface. 3D surface profiles, etc., as will be described in more detail below with respect to Figures 6A and 6B). Storage portion 414 may include a portion of computer memory for storing certain software, routines, data, etc. for processing operations of device configuration 110 and the like.

Figures 3A and 3B illustrate certain components relative to Figures 1A-2, including certain components of a kinematic mechanism arrangement 220 that includes a rotation mechanism 214' of the machine body 200 of the CMM 100 (embodied in the probe head). 213′ in). 3A illustrates the vision probe 300 in a vertical orientation (e.g., similar to how some prior art systems such as some vision systems are primarily operated to only move the focus position up and down along the Z-axis direction of the machine coordinate system to Get an image stack containing artifact images). As shown in Figure 3A, the workpiece WP has a workpiece surface WPS1 having an angular direction (at angle A1). Note that in the illustration of FIG. 3A , the Z-axis of the machine coordinate system is parallel to the optical axis OA of the vision probe 300 . It will be understood that if the vision probe 300 is simply moved up and down along the Z-axis of the MCS by the Z-axis sliding mechanism 227 (including movement of the Z-axis moving member 224 within the column 223), the optical axis (Z-axis) of the vision probe 300 ) can be in the same direction as the Z-axis of the machine coordinate system and the image stack acquisition axis ISAA. The workpiece surface WPS1 is shown at an angle A1 relative to the horizontal plane of the MCS. In comparison, workpiece surface WPS2 of workpiece WP is shown generally parallel to the horizontal plane.

3B illustrates a vision probe 300 angled relative to the horizontal plane of the MCS (at angle "A-H") and the vertical plane of the MCS (at angle "A-V") in accordance with various embodiments of the present disclosure, as disclosed by The CMM 100 can achieve this. As will be described in greater detail below, the CMM 100 is capable of operating its three sliding mechanisms (i.e., x-, y-, and z-axis sliding mechanisms 225-227), which are orthogonal to each other and each only along the respective normal direction of the MCS. (intersecting the X, Y and Z axes/directions to generate motion) and a rotation mechanism 214' (embodied in the probe head 213') to move/orient the vision probe 300. Therefore, the CMM 100 can freely move the vision probe 300 relative to the workpiece WP along multiple axes simultaneously including rotation about any axis to obtain an image stack at a specified angle. More generally, the movement mechanism configuration 220 (including the X, Y, and Z sliding mechanisms 225-227 and the rotation mechanism 214') supports and enables the vision probe 300 to move in mutually orthogonal X, Y, and Z directions and to move relative to each other. At an ideal angle/direction to the workpiece surface to be measured.

In the example shown in FIG. 3B , vision probe 300 has been rotated about horizontal rotation axis RA2 passing through rotation point R2 (eg, via a U-joint or other component of rotation mechanism 214 ′ of probe head 213 ′) to point Angle A-H and for this reason the optical axis OA of the vision probe 300 is approximately perpendicular to the workpiece surface WPS1. In Figure 3B, the ability of the rotation mechanism 214' of the probe head 213' to rotate the vision probe 300 around the Z-axis of the machine coordinate system is determined by the rotation axis passing through the rotation point R1 at the top of the probe head 213'/rotation mechanism 214' RA1 is shown. Rotation about the horizontal axis is based on the rotation axis RA2 (i.e. due to pointing to the page (while represented as a single point) is illustrated.

In Figure 3B, an example image stacking range SR-3B for determining the 3-dimensional surface profile of the workpiece surface WPS1 is shown. Workpiece surface WPS1 may have various workpiece features (eg, surface features) that may be above or below the average planar location of workpiece surface WPS1, as will be described in greater detail below with respect to FIG. 7A. In some embodiments, it may be desirable to have the range of individual focus positions of the image stack extend a distance above and below the workpiece surface. As shown in FIG. 3B , the example image stacking range SR-3B may be significantly smaller than the image stacking range SR-3A of FIG. 3A (i.e., the image stacking range required to cover all surface points of the workpiece surface WPS1 in the direction shown in FIG. 3A ), this is due to the fact that the vision probe 300 in Figure 3B is oriented such that its optical axis OA is approximately perpendicular to the workpiece surface WPS1, as in contrast to the orientation in Figure 3A. In Figure 3B, the angle of the optical axis OA (and the image stack acquisition axis ISAA) relative to at least a portion of the workpiece surface WPS1 is denoted "A-P", which in the illustrated example is approximately 90 degrees/vertical. Figure 3B also shows the angle of workpiece surface WPS1 relative to horizontal plane "A-W" (eg, corresponding to angle A1 of Figure 3A). Depending on the particular angle A-W in each embodiment, the rotation mechanism 214' can be adjusted to ensure that the optical axis OA (and ISAA) of the vision probe 300 is generally perpendicular to at least a portion of the workpiece surface WPS1, as will be discussed below with reference to Figures 7A-7C Describe in more detail.

Figure 4 shows a 2-dimensional perspective view of the motion of the vision probe 300, and Figure 5 shows a 3-dimensional perspective view thereof, for obtaining an image stack (eg, as an example, including eleven images, as described below with respect to Figures 6A and 6B shown and described in more detail). As shown in Figures 4 and 5, in one specific example, the vision probe 300 can move through at least eleven axial image acquisition positions I1-I11 to acquire eleven images with corresponding axial focus positions F1-F11. image. It will be appreciated that each axial focus position F1 - F11 may be positioned along the image stack acquisition axis (ISAA) of vision probe 300 .

4 and 5 illustrate the 2-dimensional coordinates and 3-dimensional coordinates of each of the axial image acquisition positions I1-I11 and the axial focus positions F1-F11. Typically, some prior art systems that have acquired image stacks do so only in the vertical direction (ie, only along the Z-axis of the machine coordinate system). More specifically, according to the prior art, an imaging system (eg, a machine vision system, etc.) may be configured to move the focus position of the system up or down along a vertical Z-axis corresponding to the Z-axis of the machine coordinate system. On the other hand, according to the present disclosure, the designated direction for collecting the image stack is not limited thereto. As shown herein, it is now possible to collect image stacks at an angle using components of the CMM 100 in conjunction with the disclosed vision probe 300. Therefore, according to the present disclosure, instead of referring to the "Z-axis" of the machine coordinate system as the default optical axis for image acquisition as in the prior art, a vision probe that acquires an image stack can be arranged and oriented in any direction and at any angle. The optical axis of needle 300 may in some cases correspond to and/or be referred to as the "image stack acquisition axis" (ISAA or ISA axis).

Referring to Figure 4, generally, the ISA axis (ISAA) may be established at the beginning of the process for acquiring an image stack. The vision probe 300 can then be moved to each new position along the ISA axis to acquire additional images. To acquire each additional image of the image stack, the optical axis OA of the vision probe 300 may be coaxial with the ISA axis. Due to the fact that movement of the vision probe 300 during such fine adjustments between image acquisition positions typically requires individual adjustments to the X, Y, and Z slide mechanisms 225-227 (e.g., in various embodiments, their may or may not all move simultaneously or proportionally), so the movement of vision probe 300 may not always be exactly along the ISA axis. However, once the movement is completed such that the vision probe 300 moves to the next axial image acquisition position to acquire the next image, the axial image acquisition position may be along the ISA axis. Furthermore, each axial focus position F1 - F11 (ie, the focus position corresponding to each acquired image) may also be along the ISA axis.

The prior art imaging systems described above that use only a single slide mechanism (eg, a Z-axis slide mechanism) to acquire a stack of images may in some cases be configured to perform specialized imaging, and thus may be less common and more expensive. In comparison, CMMs including x-, y-, and z-axis sliding mechanisms are relatively common and widely used. In accordance with the present disclosure, in various exemplary embodiments, a CMM is used to move the vision probe 300 to acquire an image stack in any direction or angle, which provides greater flexibility over utilizing a standard CMM. Additionally, due to the inclusion of high-precision X, Y, and Z-axis scale sensors 228-230 (e.g., including rotary encoders and/or other types of relative position sensors) for each of the sliding mechanism of the rotary mechanism 214 and the rotary sensor 215, Therefore the configuration having the X, Y and Z axis sliding mechanisms 225-227 and the rotating mechanism 214 can be highly accurate. In various exemplary embodiments, due in part to the direct relationship of each X, Y, and Z sensor to a single coordinate axis (and corresponding single coordinate) in the MCS, within the MCS for the corresponding The overall position determination of each coordinate can be performed relatively simply and at the same time highly accurate.

Figures 4 and 5 show examples of X, Y and Z coordinates in the machine coordinate system for each movement of the vision probe 300 to the image acquisition position I1-I11. In various embodiments, the machine coordinate system x-axis, y-axis, and z-axis may be referred to as the XS _- axis, the YS _- axis, and the ZS _- axis, respectively. The image acquisition locations I1-I11 of the vision probe 300 positioned to capture the eleven images of the image stack (images (1)-(11) in Figure 6B) correspond to the ten images of the image stack on which the vision probe 300 is focused. The axial focus positions F1 to F11 of an image. In the example shown, all image acquisition positions I1-I11 and axial focus positions F1-F11 are along the image stack acquisition axis (ISAA). For image stack 650 of Figure 6B, when vision probe 300 is located at image acquisition position I1, it focuses on axial focus position F1 to capture an image of the image stack (1).

More specifically, as shown in FIG. 4 , for the image acquisition position I1 , the corresponding MCS coordinates of the reference position of the vision probe 300 are at IX1 and IZ1 . In the next image acquisition position I2, the MCS coordinates may be IX2 and IZ2. At the next image acquisition position I3, the MCS coordinates may be IX3 and IZ3. For the remaining image acquisition positions I4-I11, the corresponding MCS coordinates of the reference position of the vision probe 300 are similarly at IX4-IX11 and IZ4-IZ11, respectively. In order to move the vision probe 300 from the image acquisition position I1 to the image acquisition position I2, the X-axis sliding mechanism 255 is adjusted to move from IX1 to IX2. Similarly, Z-axis slide mechanism 227 is adjusted to move from IZ1 to IZ2. Regarding Figure 5, for the image acquisition position I1, the corresponding MCS coordinates are at IX1, IY1 and IZ1. In the next image acquisition position I2, the MCS coordinates may be IX2, IY2 and IZ2. At the next image acquisition position I3, the MCS coordinates may be IX3, IY3, and IZ3. In order to move the vision probe 300 from the image acquisition position I1 to the image acquisition position I2, the X-axis sliding mechanism 255 is adjusted to move from IX1 to IX2. Similarly, the Y-axis sliding mechanism 226 is adjusted to move from IY1 to IY2, and the Z-axis sliding mechanism 227 is adjusted to move from IZ1 to IZ2. Similar movements are performed for movements to the remaining image acquisition positions.

In some embodiments, such adjustment of sliding mechanisms 225-227 may be relatively simultaneous such that vision probe 300 may generally follow the image stack acquisition axis ( ISAA) mobile. However, the movements of each sliding mechanism 225-227 need not be exactly proportional or simultaneous throughout the motion, and the movement of vision probe 300 between positions may not be entirely centered along the ISA axis. That is, unlike prior art systems that utilize a single sliding mechanism to result in movement along multiple image stack acquisition axes at all times, movement of each sliding mechanism 225-227 according to various embodiments of the present disclosure can result in movement along multiple Determination and/or combination of movements of axes. However, in various exemplary embodiments, at the end of the entire movement from position I1, vision probe 300 will be positioned at position I2, which is along the ISA axis and/or otherwise allows the vision probe to The optical axis of needle 300 is coaxial with the ISA axis.

As will be described in more detail below, in some embodiments it may be desirable to have the focus position of at least a portion of the workpiece surface WPS1 approximately correspond to a focus position in the middle of the range of focus positions of the image stack. For example, in the illustrated image stack of eleven (11) images with corresponding focus positions F1 through F11, it may be desirable that at least a portion of the workpiece surface be generally in focus at a generally axial focus position F6, which generally corresponds to that in the image The middle of the range of stacking, as will be described in more detail below with respect to Figures 6A and 6B. As discussed herein, it may also be desired that at least a portion of the workpiece surface WPS1 (and/or the general or average angular orientation of the workpiece surface or a portion thereof) is approximately/nominally perpendicular to the ISA axis, as shown in Figures 4 and 5. Such features have also been previously described with respect to the potential scan range SR in Figures 3A and 3B, and will be described in more detail below with respect to the scan ranges SR1 and SR2 of Figures 7B and 7C. More specifically, in accordance with the present disclosure, by orienting the vision probe 300 so that the image stack acquisition axis (ISAA) is approximately perpendicular to at least a portion of the workpiece surface being imaged (WPS1), the extent of the image stack may be relatively short while still Covers all surface point ranges of 3D workpiece features (i.e., corresponding to 3D surface features and deviations) with high accuracy.

6A and 6B illustrate how a stack of images obtained by the vision probe 300 in accordance with the present disclosure can be used to determine the ZP position of a point on the workpiece surface along the ZP axis, which can be generally/nominally perpendicular to the workpiece. surface. As used herein, the "ZP axis" may correspond to the z-axis of the probe coordinate system and/or the optical axis of the vision probe 300, which may not coincide with the z-axis of the MCS when the vision probe 300 is angled or tilted. coincide. In various embodiments, an image stack is obtained with the CMM 100 operating in point autofocus (PFF) mode (or similar mode) to determine the ZP height (ZP position) of the workpiece surface along an axis approximately perpendicular to the workpiece surface. The PFF image stack can be processed to determine or output a ZP height coordinate map (eg, a point cloud) that quantitatively indicates a set of 3-dimensional surface coordinates (eg, corresponding to the surface shape or profile of the workpiece).

Specifically, FIGS. 6A and 6B illustrate the relationship between determining the direction along the image stack acquisition axis (eg, which is parallel to the vision probe 300 or the ZP axis of the probe coordinate system (PCS)) for a point on the workpiece surface. Operations related to ZP position. In a configuration where the image stack acquisition axis ISAA is parallel to the Z axis of the machine coordinate system, the relative position has been referenced in some existing systems as corresponding to the Z height of the surface point, although more generally the image stack acquisition axis The ISAA can be oriented in any direction, as disclosed herein.

As shown in Figures 6A and 6B, the focus position can move within a range of position Zp(i) along the direction of the image stack acquisition axis ISAA, which direction can correspond to the focus axis at each image acquisition position. Vision probe 300 can capture image (i) at each location Zp(i). For each captured image (i), a focus metric fm(k,i) can be calculated based on a region or sub-region of interest ROI(k) in the image (e.g., a set of pixels) (e.g., where the corresponding surface points In the center of the region or sub-region of interest ROI(k)). Along the direction of the image stack acquisition axis ISAA when capturing image (i), the focus measure fm(k,i) is related to the corresponding position Zp(i) of the vision probe 300 and the corresponding focus position. This produces focus curve data (e.g., a set of focus measures fm(k,i) at position Zp(i), which is one type of focus peak determination data set), which may simply be called a "focus curve" ” or “Autofocus Curve”. In one embodiment, the focus metric may involve a calculation of the contrast or sharpness of a region of interest in the image.

The ZP position corresponding to the peak of the focus curve (eg, Z _p k601 in Figure 6A), which corresponds to the optimal focus position along the image stack acquisition axis, is the ZP position used to determine the region of interest of the focus curve. It will be understood that although for illustration purposes the image stack is shown as comprising eleven images (Image(1)-Image(11)), in actual embodiments a smaller or greater number of images may be utilized (e.g. 100 or more).

As indicated by the focus curves generated for images (1)-(11), in the example shown, image (6) appears to be close to or in optimal focus (e.g., farther away from image (6) than to the workpiece surface. Far images appear increasingly out of focus, and other images may appear increasingly blurry, with features in the middle of ROI (1) (not shown) appearing to be most in focus in image (6). When the focus metric value is based on contrast as described above, one approach involves comparing the center pixel of the ROI to its neighboring pixels in the ROI in terms of color/brightness etc. By finding the image with the highest overall contrast (corresponding to the focus position when the image was acquired), an indication/measurement of the relative ZP position of the surface point (e.g. at the center of the ROI) can be obtained along the optical axis OA and the image stack acquisition axis ISAA .

In FIG. 6B as described above, the central region of interest ROI ( 1 ) is seen generally focused on image ( 6 ), which corresponds to position Zp ( 6 ) along the optical axis of vision probe 300 . The optical axis corresponds to the Zp axis in the probe coordinate system (PCS), and may also be coaxial with the image stack acquisition axis ISAA when acquiring each image using the vision probe 300. In this way, it is possible to determine that the surface point on the workpiece surface corresponding to the center of the ROI (1) is located at the relative position Zp (6), since this position approximately corresponds to the focus position of the image (6) in the image stack. It will be understood that in some cases, the determined peak focus position may fall between two images in the image stack, and the focus peak position for them may be obtained by fitting the focus curve to the focus metric value determined for the image. interpolation or other techniques to determine.

In some embodiments, it may be desirable to have the images of the image stack roughly evenly spaced within the image stack, which may help ensure an even distribution of data points along the focus curve and/or serve to simplify certain calculations (e.g., interpolation, etc. ), or otherwise used to assist/improve certain algorithm operations. However, in some cases it is also possible to relatively accurately determine the focus curve from a stack of images when the images are not all evenly spaced (e.g. possibly due to X, The Y and Z axis sliding mechanisms 225-227 result in, for example, how many small increments of movement can be accurately performed, etc.).

If uniform spacing of all images in the image stack is desired, in some embodiments it may be desirable to utilize certain orientations of the vision probe 300 for which the motion used to acquire the image stack can be determined by the specific CMM X, Y, and Z Limitations/feature support for shaft sliding mechanisms 225-227. For example, if the X, Y, and Z axis slide mechanisms 225-227 each have a minimum increment of motion (e.g., 1 um), and if a 45 degree angle is used for the ISA axis, then in one example embodiment, for each image At the acquisition location, the X, Y and Z axis slide mechanisms 225-227 to be moved can be moved in the same increments (e.g. 1um) so that the spacing between each image in the image stack will be the same. According to similar principles, each of the X, Y and Z axis slide mechanisms 225-227 can move by a different amount for each image acquisition position, but for this purpose, the X movement amount/increment is for each image acquisition position. The Y movement amount/increment can be the same for the movement between each image acquisition position, and the Z movement amount/increment can be the same for the movement between each image acquisition position. In accordance with such movement, the image acquisition positions will correspond to and/or define the image stack acquisition axis ISAA, for which the probe can be oriented such that at each image acquisition position the optical axis OA of the vision probe 300 can be approximately/nominally Coaxial with image stack acquisition axis ISAA.

According to similar principles, if there is a minimum increment of adjustment for the angular orientation of the vision probe 300 (e.g., based on the minimum obtainable increment/adjustment of the movement of the rotation mechanism 214 for the angular orientation of the vision probe 300 ), it is also possible to make the motion of the X, Y and Z axis sliding mechanisms 225-227 have ISAA corresponding to such angular directions. In some embodiments, for the entire system, the optimal/most accurate positioning of the vision probe may be found based at least in part on the smallest increment of motion of the rotation mechanism 214 and/or the X, Y, and Z axis sliding mechanisms 225-227. The optical axis OA of 300 is aligned with the image stack acquisition axis ISAA for the desired orientation of the vision probe 300 . Specifically, this desired orientation of the vision probe 300 for capturing the image stack may be found based on the movement/adjustment capabilities of the CMM 100 for adjusting the position/angular orientation of the vision probe 300. In one particular example embodiment, in accordance with the above principles/examples, a 45 degree angle (or a trigonometrically similar angle, such as a 135 degree, 225 degree or 315 degree angle) may be utilized in certain circumstances to orient the vision probe 300 (e.g. , relative to a horizontal or vertical plane, such as one or more of the XY plane, XZ plane and/or YZ plane of the MCS).

Referring further to Figure 6B, the region of interest ROI(2) is shown to be positioned diagonally relative to the region of interest ROI(1). As an example, if the region of interest ROI(2) is not in focus at any point within the 11 images of the example image stack 650, then in order to find the focus position of the surface point corresponding to ROI(2), it may be necessary to evaluate Additional images and/or expansion of the range of the image stack may be required (eg, to acquire an image stack with a greater number of images and a larger corresponding range of focus positions). In some embodiments, image stacks of 100 or more images may often be acquired/utilized. For example, referring to Figure 7A, the surface point centered on the middle of ROI(1) can be at the bottom of the cylindrical hole that is the workpiece feature WPF1, while the surface point corresponding to ROI(2) can be at the top edge of the cylindrical hole , for which a larger image stacking range as well as additional images (e.g., for all surface points of the workpiece feature WPF1 covering the workpiece surface WPS1) may be required/utilized.

Figure 7A shows sample workpiece WP1 having respective workpiece surfaces WPS1, WPS2, WPS3 and workpiece features WPF1, which are holes defined in workpiece surface WPS1, WPF2, and WPF3C, which are between workpiece surfaces WPS2 and WPS3 certain geometric features defined on the edge interface) and WPF3A and WPF3B (two holes defined in the workpiece surface WPS3). As described above with reference to Figure 3B, the workpiece surface or workpiece feature to be measured will be located within the image stacking range SR-3B to determine the 3-dimensional surface profile of the workpiece surface or workpiece feature. As shown in Figure 7A, each workpiece feature includes a surface that is higher or lower than the general plane or average plane of the workpiece surfaces on which the workpiece feature is defined. Therefore, in various embodiments, imaging of workpiece features may require the use of an image stacking range (or scan range SR) large enough to cover all surfaces/surface points of workpiece features at different ZP heights.

7B is a schematic diagram illustrating the distal end of vision probe 300 whose optical axis OA and image stack acquisition axis ISAA are oriented generally perpendicularly (i.e., parallel to z-axis of the MCS), the workpiece WP1 has an angled workpiece surface WPS1 which includes the workpiece feature WPF1. Figure 7C is a schematic illustration of the distal end of vision probe 300 with its optical axis OA and image stack acquisition axis ISAA oriented at an angle so as to be generally/nominally perpendicular to the angled workpiece surface WPS1 of workpiece WP1.

Generally speaking, Figures 7B and 7C can be understood as showing the desired scanning range for covering the 3-dimensional surface topography of the workpiece surface WPS1 (e.g., the range of Figure 7C compared to Figure 7B), depending on the visual The orientation of probe 300 relative to the workpiece surface WPS1 to be measured. For example, scan range SR1 with the orientation of FIG. 7B is significantly larger than scan range SR2 with the orientation of FIG. 7C , thereby being able to cover the 3-dimensional surface topography of workpiece surface WPS1 (eg, including workpiece features WPF1 ). Therefore, adjusting the angle/orientation of the vision probe 300 as in Figure 7C so that the optical axis OA is approximately perpendicular to the workpiece surface WPS1 and/or the workpiece feature WPF1 is technically advantageous in reducing the required scan range, This in turn can shorten scan times and/or reduce the number of images required to form an image stack (eg, with a desired image density).

As shown in FIG. 7B , in addition to the scanning range SR1 for image stacking being significantly larger than the scanning range SR2 of FIG. 7C , the vision probe 300 is also oriented at a relatively acute angle with respect to the workpiece surface WPS1 , which may reduce imaging quality or block the workpiece. Feature imaging of certain parts/aspects of WPF1. For example, sharp angles may reduce imaging quality because less imaging light is reflected back to the vision probe 300 or the like. As another example, in Figure 7B, the upper corner of the bottom of the cylindrical hole workpiece feature WPF1 at surface point SP3 is shown as being invisible to the vision probe 300 (i.e., the upper edge of the cylindrical hole is blocked in the direction shown (View of the corner of the surface point SP3 of the cylindrical hole). In comparison, in FIG. 7C , by orienting vision probe 300 generally perpendicular to workpiece surface WPS1 and/or at least a portion of workpiece feature WPF1 , vision probe 300 may have a better angle to detect features on workpiece surface WPS1 Various workpiece features (e.g., WPF1) are imaged (e.g., better angles for reflected imaging light, ability to view corners at surface point SP3, etc.). Therefore, in some embodiments, the vision probe 300 in the direction of FIG. 7C may be able to provide a more accurate view of the workpiece surface WPS1 in addition to having a smaller scan range SR2 compared to the scan range SR1 of FIG. 7B . 3D surface profile.

In various implementations, it may also be desirable to perform different scans in different directions with vision probe 300 (including acquiring different image stacks). For example, workpiece WP1 is considered to include workpiece surfaces WPS1, WPS2 and WPS3. In one embodiment, vision probe 300 may be positioned as shown in Figure 7B (e.g., tilted 0 degrees relative to vertical) to acquire an image stack for scanning workpiece surface WPS2, and then oriented as shown in Figure 7C (e.g., tilted 45 degrees relative to vertical) to capture an image stack for scanning workpiece surface WPS1, and then oriented (eg, tilted 90 degrees relative to vertical) to capture an image stack used for scanning workpiece surface WPS3.

In some embodiments, the scan/image stack can be made to include all or portions of multiple workpiece surfaces. For example, the image (and field of view) used to scan workpiece surface WPS2 at a 0 degree inclination may also include all or part of workpiece surface WPS1 (and/or workpiece surface WPS3). Such a process (where multiple image stacks can include at least some common surface points scanned/imaged from different directions) can help further validate the 3D position of each surface point and/or enable various 3D data corresponding to different workpiece surfaces to form a complete or partial 3D representation of the workpiece WP1. For example, in various embodiments, 3D profiles of various surfaces may be "stitched together" or otherwise combined to form a full or partial 3D representation of workpiece WP1. Additionally, certain workpiece features (e.g. WPF2/WPF3C) may have certain dimensions/aspects that can be included in scans of multiple surfaces (e.g. WPS2 and WPS3), and scans of each surface can be exploited/combined to Determine the overall properties/dimensions/3D contours of the workpiece feature WPF2/WPF3C. Such possible operations and processes illustrate another advantage of the present disclosure, as some prior art systems are typically only capable of acquiring image stacks from a single direction (e.g., along the Z-axis of the MCS), whereas the present disclosure enables CMM systems to Utilize a vision probe to acquire multiple image stacks from multiple directions to analyze/measure/determine the 3D profile of multiple workpiece surfaces and/or features that can be in different orientations. Such 3D data for various surfaces/features of the workpiece may then be combined or otherwise utilized to determine an overall 3D profile of all or part of the workpiece and/or certain workpiece features.

In the PFF type analysis described above with reference to Figures 6A and 6B, each focus curve (shown in Figure 6A) corresponds to a single point on the workpiece surface. That is, the peak of each focus curve represents the Zp position of a single point along the direction of the optical axis OA of the vision probe 300 . In various embodiments, PFF type analysis repeats this process for multiple surface points across the workpiece surface (eg, each with a corresponding region of interest) so that the overall profile of the workpiece surface can be determined. Typically, this process can be performed for multiple surface points within the field of view (i.e., as captured within images of an image stack), where for each image of the image stack, a specific ROI(i) corresponds to a specific ROI(i) on the workpiece surface. point (this point is preferably at the center of the ROI). Referring additionally to Figure 7B, as an illustrative example, if ROI(1) corresponds to a surface point at the bottom edge of cylindrical hole workpiece feature WPF1 (e.g., adjacent to surface point SP3), and if ROI(2) corresponds to not A surface point on the workpiece surface WPS1 in the cylindrical hole (for example, at surface point SP2), then the focus curves corresponding to the two illustrative surface points will be different and will have different focus peaks. For example, for surface point SP2, a focus curve such as that of Figure 6A would be shifted with the peak at a different location (e.g., indicating that the focus location is closer to vision probe 300 and therefore closer to the portion of the image stack shown in Figure 6B high, or even higher in portions of the image stack not shown in Figure 6B, such as in embodiments where the image stack has other images than the 11 images shown).

The total amount of movement available for the CMM 100 with the X, Y, and Z axis sliding mechanisms 225-227, if moving only along the Z axis (i.e., only the Z axis sliding mechanism 227 is used) to adjust the focus of the vision probe 300 (e.g., Similar to the techniques used to acquire image stacks in some existing machine vision systems), the total motion range of the potential image stack acquisition process will be limited to the maximum motion range of the Z-axis sliding mechanism 227. In comparison, according to the technology of the present disclosure, the vision probe 300 can move diagonally across the entire available movement volume of the CMM 100 to acquire image stacks, which can generally provide a longer potential scan range and larger acquisition images. Stacking flexibility to scan individual workpiece surfaces from different angles.

As mentioned previously, in some embodiments, in addition to utilizing the vision probe 300 to obtain an image stack for determining the 3-dimensional surface profile, a tactile measurement probe 390 is utilized in some cases in combination with the vision probe 300 (i.e., Probes with a probe tip that physically contacts the workpiece to determine the measurement, such as a contact probe or scanning probe with the probe tip positioned to contact and slide along it in order to "scan" the workpiece surface, may also be useful. For example, after use of vision probe 300, vision probe 300 can be detached from CMM 100, and tactile measurement probe 390 can be attached to CMM 100 and used to verify the location of certain surface points, and/or measure certain surface points. Some surface points, such as those that vision probe 300 may not image well. For example, in the embodiment of FIG. 7C , it may be difficult to stack images captured from vision probe 300 , assuming surface point SP3 is directly below surface point SP2 along optical axis OA of vision probe 300 in the orientation shown. Determine the exact location of surface point SP3. In this case, the tactile measurement probe 390 may be used to verify the location of certain surface points (eg, along the edge of the cylindrical hole workpiece feature WPF1 and/or at its bottom corners, such as surface points SP3 and SP4, etc.).

As mentioned previously, in some embodiments, it may be desirable to have the optical axis of vision probe 300 generally perpendicular to the workpiece surface being scanned (ie, for which the image stack is captured). It should be noted that the optical axis of the vision probe 300 may be perpendicular to only a portion of the workpiece surface, or in some cases may not actually be perpendicular to any particular portion of the workpiece surface, but only perpendicular to the overall or average, etc., of the workpiece surface. etc. direction. For example, if the workpiece surface is particularly uneven and/or includes numerous workpiece features that create complex or uneven 3D contours/surface topography, the optical axis/image stack acquisition axis (OA/ISAA) may not be consistent with any specific feature of the workpiece surface. Parts are not exactly perpendicular, but may be approximately/nominally perpendicular to the overall, mean and/or general equal orientation or principal angles of the workpiece surface.

Still referring to Figures 7A-7C, additional implementation examples of CMM 100 for obtaining and using image stacks to determine a "depth map" and/or "surface topography" of a workpiece surface will be described. In some cases, it may be described that the entire workpiece surface may be at a "primary angle," which corresponds to the workpiece angle A-W described with respect to Figure 3B, which is the angle formed between the workpiece surface and the horizontal plane in which the workpiece lies. As mentioned previously, in some embodiments it may be advantageous or otherwise desirable to have the image stack acquisition axis ISAA substantially perpendicular to the workpiece surface at a principal angle (A-W). Even if the image stack acquisition axis ISAA is not exactly perpendicular to the general direction of the workpiece surface, this problem can be partially solved by processing the image data according to the specific application (for example, including how the user wishes to present the image data, etc.). More specifically, when using image stacking to determine the depth map and/or surface topography of a workpiece surface, if it is determined that the main angle (A-W) perpendicular to the workpiece surface is not perfectly aligned with the ISA axis but forms an angle with the ISA axis ( i.e., the workpiece surface is not exactly perpendicular to the ISA axis), then as part of the image data processing, such angular offsets can be subtracted or otherwise compensated such that the workpiece surface can generally be determined/displayed in a horizontal plane across the entire workpiece surface Depth maps or surface topography (e.g., may be desired for certain presentations and/or analyses, etc.). In some embodiments, if a user or system is visually or otherwise evaluating a workpiece surface for defects, it may be preferable to have a generally horizontal representation of the workpiece surface, for which the defects may be more easily identified/determined as being different from other Height deviations from a horizontal workpiece surface (eg, defects and/or other deviations based on coordinates above or below those of a generally horizontal surface).

In various exemplary embodiments of the CMM 100, the dominant angles (A-W) of the workpiece surface to be measured may first be determined in order to know at what angle to orient the vision probe 300 to image the workpiece surface. In various exemplary embodiments, the dimensions and characteristics of the workpiece to be measured, including its principal angles, may be known, for which the CMM 100 may be used to perform precision measurements and/or inspections. Once the dominant angle is known or determined, the desired angular orientation of the vision probe 300 can be determined (eg, to be generally normal to at least a portion of the workpiece surface). As described above, by orienting the vision probe 300 in this manner relative to the workpiece surface, the same number of more spaced (i.e., corresponding focus positions between images are further apart) is required to cover a larger scan range. The desired range of the image stack can be made relatively smaller/shorter compared to the image stack, thereby allowing faster acquisition of the image stack and/or allowing for a denser image stack (i.e., corresponding focus positions between images) The same number of images are collected with smaller spacing).

7B and 7C, program instructions, when executed by one or more processors of CMM 100, may cause the one or more processors to acquire a first image stack as shown in FIG. 7C and to acquire a third image stack as shown in FIG. 7B. Two images stacked. In FIG. 7C , workpiece surface WPS1 may be designated as the first workpiece surface, and the orientation of vision probe 300 (which is the first orientation) may be used to acquire a first image stack of the first workpiece surface of workpiece WP1 . In FIG. 7B , workpiece surface WPS2 may be designated as a second workpiece surface that is oriented at a different angle than first workpiece surface WPS1 , and the orientation of vision probe 300 in the second orientation that is different from the first orientation may be used A second image stack of a second workpiece surface of workpiece WP1 is acquired. In the orientation shown in Figure 7B, the second image stack may have a field of view that primarily includes workpiece surface WPS2 (second workpiece surface) but may also include all or part of workpiece surface WPS1 (first workpiece surface). Similarly, in the orientation shown in Figure 7C, the first image stack may have a field of view that includes primarily workpiece surface WPS1 (first workpiece surface) but may also include all or part of workpiece surface WPS2 (second workpiece surface).

In various embodiments, in addition to focus curve data that may be determined based at least in part on analysis of a first image stack (e.g., with respect to FIG. 7C ), focus curve data may also be determined based at least in part on an analysis of a second image stack (e.g., with respect to FIG. 7C ). , with respect to FIG. 7B ) determines additional focus curve data, wherein the additional focus curve data indicates the 3-dimensional positions of a plurality of surface points on a second workpiece surface of the workpiece (eg, workpiece surface WPS2 ). In various embodiments, the system may determine and/or display the first workpiece surface WPS1 based on at least focus curve data determined based on analysis of the first image stack but not based on analysis of the second image stack. A 3D representation of at least part of it. Similarly, the system may determine and/or display 3 of at least a portion of the second workpiece surface WPS2 based on at least focus curve data determined based on analysis of the second image stack rather than based on analysis of the first image stack. Wei said.

For example, in some embodiments in which the first image stack and the second image stack may each contain a portion or all of workpiece surfaces WPS1 and WPS2, with focus curve data determined for first workpiece surface WPS1 based on analysis of the second image stack (For this reason, the second image stack acquisition axis ISAA2 is not approximately perpendicular to at least a part of the first workpiece surface WPS1 and is in particular further from vertical than the first image stack acquisition axis ISAA1 ) Compared to, based on the analysis of the first image stack The focus curve data determined for the first workpiece surface WPS1 (for which the first image stack acquisition axis ISAA1 may be approximately perpendicular to at least a portion of the first workpiece surface WPS1 ) may be considered or determined to be more accurate and/or have a higher Quality/certainty.

As described in more detail in U.S. Patent No. 8,581,162 (the entire contents of which is incorporated herein by reference), the certainty of certain focused peaks and/or Z-height quality metadata analysis may indicate the reliability of certain 3-dimensional data determined properties and/or quality (e.g. related to the region of interest in the image stack). Although the '162 patent performs such an analysis with respect to the quality/reliability of determining the coordinates of adjacent workpiece surface points in a single image stack (i.e., acquired only along the Z-axis direction of the machine coordinate system), in accordance with the present disclosure, certain Similar principles can be applied to consider the quality/reliability of determining the coordinates of workpiece surface points in one image stack relative to another image stack (e.g. acquired at different angles). For example, in some embodiments, focus curve data determined for an image stack acquired with an image stack acquisition axis ISAA approximately perpendicular to a portion of the workpiece surface may be less useful in determining the coordinates of a workpiece surface point on that portion of the workpiece surface. Image Stacking Image stacking with a lower vertical acquisition axis is relatively more accurate. In certain embodiments, as discussed above, the greater accuracy is due at least in part to a more vertical orientation of the vision probe/optical axis relative to the workpiece surface, which results in more imaging light being reflected back to the vision probe 300 (For example, this may result in higher focus peaks and higher correspondence reliability and/or quality for 3D data). In some embodiments, the relative accuracy may also be due in part to the fact that in a given image of the image stack, more adjacent workpiece surface points/pixels are simultaneously focused in a more vertical direction, thus allowing higher determination of Focus metric value (e.g., based on contrast or other focus metric). In comparison, focus curve data determined for an image stack acquired using an image stack acquisition axis ISAA that is relatively far from normal to a portion of the workpiece surface may be relatively useful in determining the coordinates of a workpiece surface point on that portion of the workpiece surface. Inaccurate. In certain embodiments, as discussed above, the lower accuracy is due at least in part to a less vertical orientation of the vision probe/optical axis relative to the workpiece surface, which results in less imaging light being reflected back to the vision probe 300 (for example, this may result in lower focus peaks and lower corresponding reliability and/or quality of 3D data). In various embodiments, the relative inaccuracy may also be due in part to fewer adjacent workpiece surface points/pixels being focused simultaneously (i.e., due to the tilt of that portion of the workpiece surface relative to the image stack acquisition axis), in some cases Only "strips" of relatively tilted workpiece surfaces at the same Z distance in the probe coordinate system may be accurately focused at the same time, resulting in less "focus" in the region of interest in a given image of the image stack Pixels/surface points that contribute a higher amount to the overall focus metric of the region of interest with the corresponding central surface point/pixel. More specifically, in some cases, more focus pixels in a given image that are simultaneously in the region of interest may result in a higher focus peak, for which the determination of the focus peak location may be more accurate (e.g., for noise or other factors less sensitive), resulting in better focus peak certainty.

As another example, in various embodiments, the CMM 100 may acquire a co-imaged surface point, such as surface point SP2 on a first portion of the first workpiece surface WPS1 that is in the first image stack and the second image stack. The stack is imaged, with the first image stack acquisition axis ISAA1 (of FIG. 7C ) being closer to the first portion perpendicular to the first workpiece surface WPS1 than the second image stack acquisition axis ISAA2 (of FIG. 7B ). Focus curve data determined based at least in part on analysis of the first image stack may indicate a first 3-dimensional location of co-imaged surface point SP2 (e.g., in one example, it may correspond to the determined first set of coordinates , such as (XP2C, YP2C, ZP2C)). On the other hand, focus curve data determined based at least in part on analysis of the second image stack may indicate a second 3-dimensional location of the co-imaged surface point SP2 (e.g., in one example may correspond to the second determined set of coordinates, such as (XP2B, YP2B, ZP2B). Note that in various embodiments, the second determined 3-dimensional position (eg, at the determined coordinates XP2B, YP2B, ZP2B) may be different from the first determined 3-dimensional position position (e.g., at determined coordinates used as part of a set of 3D data for the workpiece. As mentioned above, such a technique may be advantageous because images acquired with image stacking acquisition axis ISAA (which is approximately perpendicular to the workpiece surface and/or a portion of the workpiece feature) The focus curve data determined for the stack may be relatively more accurate than the focus curve data determined for the image stack acquired with the image stack acquisition axis ISAA, which is less perpendicular to the workpiece surface and/or a portion of the workpiece feature. Therefore, for surfaces point SP2, the determined first 3-dimensional position (for example, having determined coordinates XP2C, YP2C, ZP2C) may be more accurate than the determined second 3-dimensional position (for example, having determined coordinates XP2B, YP2B, ZP2B), And it may therefore be advantageous to use the determined first 3-dimensional position as part of the 3-dimensional data set to represent the surface point SP2 of the workpiece WP1.

Figure 8 is a method of measuring a workpiece surface by using a CMM system including a movement mechanism configuration as described in Figures 1-7C to move a vision probe along multiple axes and at desired angles/directions relative to the workpiece surface. flow chart. The method usually consists of four steps.

Block 802 includes the steps of operating a coordinate measuring machine (CMM) system including: (i) a vision probe 300 configured to measure the workpiece WP based on image light transmitted along an optical axis OA of the vision probe 300 The surface imaging of moving the vision probe 300 in the y-axis and z-axis directions; and (iii) a rotation mechanism 214 coupled between the z-axis sliding mechanism and the vision probe 300 and configured to move the vision probe 300 The needle 300 is rotated to different angular directions relative to the z-axis of the machine coordinate system.

Block 804 includes the step of adjusting the orientation of the vision probe 300 using a rotation mechanism so that the optical axis OA of the vision probe 300 is directed toward the surface of the workpiece WP, wherein the optical axis OA of the vision probe 300 is not parallel to the z-axis of the machine coordinate system. , and corresponds to the image stack acquisition axis ISAA. As discussed above, in various embodiments, the optical axis OA may be approximately/nominally perpendicular to at least a portion of the workpiece surface, for which the workpiece surface may be angled (eg, may not be horizontal within the machine coordinate system).

Block 806 includes the step of acquiring an image stack including a plurality of images, each image having a corresponding focus position of the vision probe 300 along the image stack acquisition axis. Acquisition of the image stack includes: (i) adjusting a plurality of sliding mechanisms 225-227 to move the vision probe 300 from a first image acquisition position to a second image acquisition position respectively along the image stack acquisition axis, wherein the vision probe 300 300 collects a first image and a second image of a plurality of images at a first image acquisition position and a second image acquisition position respectively; and (ii) adjusting a plurality of sliding mechanisms 225-227 to move the vision probe 300 from also along The second image acquisition position of the image stack acquisition axis moves to a third image acquisition position, where the vision probe 300 acquires a third image of the plurality of images at the third image acquisition position.

Block 808 includes the step of determining focus curve data based at least in part on analysis of images of the image stack, wherein the focus curve data is indicative of 3-dimensional locations of a plurality of surface points on the workpiece surface.

While preferred embodiments of the present disclosure have been shown and described, many variations in the arrangement of features and sequences of operations shown and described will be apparent to those skilled in the art based on this disclosure. Various alternative forms may be used to implement the principles disclosed herein. Additionally, the various embodiments described above may be combined to provide further embodiments.

Claims (21)

1. A coordinate measuring machine system, comprising:

a vision probe, comprising:

a light source;

an objective lens inputting image light generated by a workpiece surface illuminated by the light source and transmitting the image light along an imaging optical path, wherein the objective lens defines an optical axis of the vision probe, the optical axis extending at least between the objective lens and the workpiece surface;

a camera that receives imaging light transmitted along the imaging light path and provides an image of the workpiece surface;

a slide mechanism arrangement comprising an x-axis slide mechanism, a y-axis slide mechanism, and a z-axis slide mechanism, each configured to move the vision probe in mutually orthogonal x-axis, y-axis, and z-axis directions, respectively, within a machine coordinate system;

a rotation mechanism coupled between the z-axis slide mechanism and the vision probe and configured to rotate the vision probe to different angular orientations relative to a z-axis of the machine coordinate system;

one or more processors; and

a memory coupled with the one or more processors and storing program instructions that, when executed by the one or more processors, cause the one or more processors to at least:

Adjusting a direction of the vision probe using the rotation mechanism to direct the optical axis of the vision probe toward a surface of the workpiece, wherein the optical axis of the vision probe is not parallel to a z-axis of the machine coordinate system and corresponds to an image stack acquisition axis;

acquiring an image stack comprising a plurality of images, each image corresponding to a focus position of the vision probe along the image stack acquisition axis, wherein acquiring the image stack comprises:

adjusting a plurality of the slide mechanisms to move the vision probe from a first image acquisition position to a second image acquisition position along the image stack acquisition axis, respectively, wherein the vision probe acquires first and second images of a plurality of images at the first and second image acquisition positions, respectively; and

adjusting the plurality of slide mechanisms to move the vision probe from the second image acquisition position to a third image acquisition position that is also along the image stack acquisition axis, wherein the vision probe acquires a third image of a plurality of images at the third image acquisition position; and

focus curve data is determined based at least in part on analysis of the images of the image stack, wherein the focus curve data is indicative of 3-dimensional locations of a plurality of surface points on a surface of the workpiece.

2. The system of claim 1, wherein as part of the analysis of the image stack, each surface point of the plurality of surface points corresponds to a center of a region of interest in the image stack, and the analysis includes determining a focal curve of each region of interest of the image stack as part of the focal curve data and a peak of each focal curve represents a 3-dimensional location of the respective surface point.

3. The system of claim 1, wherein the program instructions, when executed by the one or more processors, further cause the one or more processors to display a 3-dimensional representation of the workpiece surface based at least in part on the focus curve data.

4. The system of claim 1, wherein adjusting the plurality of slide mechanisms to move the vision probe from the first image acquisition position to the second image acquisition position comprises adjusting the x-axis slide mechanism by an x-axis image interval, adjusting the y-axis slide mechanism by a y-axis image interval, and adjusting the z-axis slide mechanism by a z-axis image interval.

5. The system of claim 4, wherein a spacing between each of the plurality of images in the image stack corresponds to the x-axis spacing, the y-axis spacing, and the z-axis spacing.

6. The system of claim 1, wherein a distance along the image stack acquisition axis between the first image acquisition position and the second image acquisition position is the same as a distance along the image stack acquisition axis between the second image acquisition position and the third image acquisition position.

7. The system of claim 1, wherein the rotation mechanism is configured to orient the vision probe in a plurality of directions, including at least:

the optical axis of the vision probe is oriented at an angle of 0 degrees relative to the z-axis of the machine coordinate system; and

the optical axis of the vision probe is oriented at a 45 degree angle relative to the z-axis of the machine coordinate system.

8. The system of claim 7, wherein the system is configured to: the stack of images is acquired with the vision probe at a 45 degree angle to the optical axis of the vision probe relative to the z-axis of the machine coordinate system.

9. The system of claim 1, wherein the rotation mechanism is not adjusted such that the orientation of the vision probe is not adjusted and remains constant during adjustment of the plurality of slide mechanisms to move the vision probe between the image acquisition positions.

10. The system of claim 1, wherein during acquisition of the image stack, an optical axis of the vision probe that is not parallel to a z-axis of the machine coordinate system and the image stack acquisition axis are substantially perpendicular to at least a portion of the workpiece surface.

11. The system of claim 1, wherein the workpiece surface is a first workpiece surface and the direction of the vision probe is a first direction and the image stack is a first image stack acquired with the vision probe in the first direction, and the program instructions, when executed by the one or more processors, further cause the one or more processors to acquire a second image stack with the vision probe in a second direction different from the first direction and with an optical axis of the vision probe directed toward a second workpiece surface of the workpiece, the second workpiece surface oriented at a different angle in the machine coordinate system than the first workpiece surface.

12. The system of claim 11, wherein the program instructions, when executed by the one or more processors, further cause the one or more processors to determine focus curve data based at least in part on analysis of the second image stack, wherein the focus curve data indicates a 3-dimensional location of a plurality of surface points on a second workpiece surface of the workpiece.

13. The system of claim 12, wherein the program instructions, when executed by the one or more processors, further cause the one or more processors to:

displaying a 3-dimensional representation of at least a portion of the first workpiece surface based at least on the focus curve data determined based on the analysis of the first image stack but not based on the analysis of the second image stack; and

a 3-dimensional representation of at least a portion of the second workpiece surface is displayed based at least on the focus curve data determined based on the analysis of the second image stack but not based on the analysis of the first image stack.

14. The system of claim 12, wherein a commonly imaged surface point on a first portion of the first workpiece surface is imaged in both the first and second image stacks, for which purpose the first image stack acquisition axis is closer to perpendicular to the first portion of the first workpiece surface than a second image stack acquisition axis, and for which purpose the focal curve data determined based at least in part on analysis of the first image stack indicates a first 3-dimensional position of the commonly imaged surface point, and the focal curve data determined based at least in part on analysis of the second image stack indicates a second 3-dimensional position of the commonly imaged surface point, the second 3-dimensional position being different from the first 3-dimensional position, and for which purpose the first 3-dimensional position is indicated and/or determined to be more reliable than the second 3-dimensional position and used as part of a set of 3-dimensional data of the workpiece in place of the second 3-dimensional position.

15. The system of claim l, wherein the objective lens has a particular magnification and is selected for the vision probe from a series of objective lenses having different magnifications.

16. A method of measuring a surface of a workpiece, comprising:

operating a coordinate measuring machine system, the system comprising: (i) A vision probe configured to image a surface of a workpiece based on image light transmitted along an optical axis of the vision probe; (ii) A slide mechanism arrangement comprising an x-axis slide mechanism, a y-axis slide mechanism, and a z-axis slide mechanism, each configured to move the vision probe in mutually orthogonal x-axis, y-axis, and z-axis directions, respectively, within a machine coordinate system; and (iii) a rotation mechanism coupled between the z-axis slide mechanism and the vision probe and configured to rotate the vision probe to different angular orientations relative to a z-axis of the machine coordinate system;

adjusting a direction of the vision probe using the rotation mechanism to direct an optical axis of the vision probe toward a surface of the workpiece, wherein the optical axis of the vision probe is not parallel to a z-axis of the machine coordinate system and corresponds to an image stack acquisition axis;

Acquiring an image stack comprising a plurality of images, each image corresponding to a focus position of the vision probe along the image stack acquisition axis, wherein acquiring the image stack comprises:

adjusting a plurality of the slide mechanisms to move the vision probe from a first image acquisition position to a second image acquisition position along the image stack acquisition axis, respectively, wherein the vision probe acquires first and second images of a plurality of images at the first and second image acquisition positions, respectively; and

adjusting the plurality of slide mechanisms to move the vision probe from the second image acquisition position to a third image acquisition position that is also along the image stack acquisition axis, wherein the vision probe acquires a third image of a plurality of images at the third image acquisition position; and

focus curve data is determined based at least in part on analysis of the images of the image stack, wherein the focus curve data is indicative of 3-dimensional locations of a plurality of surface points on a surface of the workpiece.

17. The method of claim 16, further comprising:

a 3-dimensional representation of the workpiece surface is displayed on a screen.

18. The method of claim 16, wherein adjusting the orientation of the vision probe using the rotation mechanism comprises setting an optical axis of the vision probe substantially perpendicular to at least a portion of the workpiece surface, and for this purpose, not adjusting the orientation of the vision probe further and remaining approximately constant during acquisition of the image stack.

19. The method of claim 16, wherein the workpiece surface is a first workpiece surface and the orientation of the vision probe is a first orientation, and the image stack is a first image stack acquired with the vision probe in the first orientation, and the method further comprises:

a second image stack is acquired with the vision probe in a second direction different from the first direction and with an optical axis of the vision probe directed toward a second workpiece surface of the workpiece, the second workpiece surface oriented at a different angle than the first workpiece surface.

20. The method of claim 19, further comprising:

second focus curve data is determined based at least in part on analysis of the second image stack, wherein the second focus curve data is indicative of a 3-dimensional position of a plurality of surface points on a second workpiece surface of the workpiece.

21. The method of claim 20, further comprising:

displaying a 3-dimensional representation of at least a portion of the first workpiece surface based at least on the focus curve data determined based on the analysis of the first image stack but not based on the analysis of the second image stack; and

A 3-dimensional representation of at least a portion of the second workpiece surface is displayed based at least on second focus curve data determined based on an analysis of the second image stack but not based on an analysis of the first image stack.